Parallel key action for typewriters



1960 E. e. ISRAELSON 2,966,249

PARALLEL KEY ACTION FOR TYPEWRITERS Filed May 4, 1959 2 Sheets-Sheet 1 FIG! MENTOR Y EVERT G. ASRAELSON A TTORNEY Dec. 27, 1960 [SRAELSON 2,966,249

PARALLEL KEY ACTION FOR TYPEWRITERS Filed May 4, 1959 v 2 Sheets-Sheet 2 TOTAL /1 E Y DIP INVENT OR. E VERT G. ASRAELS'ON 2 ATTORNEY United States Patent FARALLEL KEY A-C'HGN FOR TYPEWRETERS Evert G. Israelson, Rowayton, Conn., assignor to Sperry Rand Corporation, New York, N.Y., a corporation. of Delaware Filed May 4, 1959, Ser. No. 810,736 11 Claims. (Cl. 19717) This invention relates to typewriters and in particular to the key lever arrangement and operating control.

An object of the invention is to provide a typewriter key lever parallel action for use in connection with the power mechanism of a typewriter that will furnish a uniform key clip for all key lever positions.

Other objects of the invention are: to provide an adjustable upand down-stop that will not change the uniformity of the key clip from one bank of keys to another when adjusted; to provide an adjustable up-stop that adjusts the effective key dip to provide as live a keyboard action as is desirable; to provide an adjustable down-stop that adjusts the total key dip to provide a total range of adjustment in an amount to suit the operator; and to provide key tension means thatrnay be adjusted to suit the touch of the operator.

Other objects and structural details of the invention will be apparent from the following description when read in connection with the accompanying drawings, in which:

Figure 1 is a front to rear View in sectional elevation showing the relation of the parallel key mechanism to the power operating mechanism of a typewriter,

Figure 2 is a view of a portion of the key mechanism as illustrated in Figure 1 showing its use in connection with another form of powermechanism.

Figure 3 is a section taken on the line 33 of Figure 2 showing the control disk means for adjusting the.

down-stop and the key tension means, and

Figure 4 is an enlarged view of the power trip bell crank showing the angular movement thereof.

Referring to the drawings in detail, indicates generally the parallel linkage which will only be described in its relation to the printing keys and the power arm mechanism for operating type bars under the control of the. keys, as is common to Remington Rand Electric Typewriters. By adapting the structure to the requirements of other service keys or other power arm arrangements, the basic principle of the parallel linkage can be used.

The usual or standard keys 11 of a bank, forming the keyboard of the machine, are each mounted on the stem.

12 of one of a plurality of key levers 13 all of which are identical in Shape except for the position of each of, the key stems 12 thereon which are arranged in four rows, each lever 13 being part of a linkage comprising a powertrip bell crank 14, a key lever bell crank 16, and a link 17 connecting the depending portions 18 and 19 of the key lever bell crank 16 and the power-trip bell. crank 14,

respectively. The link 17-, which constitutes a stop link,v

has an elongated recess 21 in the top edge thereof in which are disposed two eccentric shafts journalled at the opposite sides of the machine and crossing each link. to

coact with the stop edges 22 and 23 thereof. The shaft 24, referred to as a down-stop, is adjacent edge 22 while.

restate Patented Dec. 2?, 1366 shaft 26, referred to as an up-stop, is adjacent the edge 23.

The power-trip bell crank 14 pivots on fulcrum wire 27 carried in the lower slotted end of cross bracket 28 while the key lever bell crank 16 pivots about fulcrum wire 29 carried in fulcrum bracket 31 which also supports a comb 32 for supporting the key levers 13 to guard against side play of the latter. The arm 33 of the powertrip bell crank 14 is equal in length from pivot to pivot, to the arm 34 on the key lever bell crank 16 while arm 19 on the power-trip bell crank 14 is equal in length to arm 18 on the key lever bell crank 16. The key lever 13 ties the arm 33 on crank 14 to the arm 34 on crank 16 and link 17 ties the arm 19 on crank 14 to the arm 18 of crank 16. The stop edges 22 and 23 on link 17 are arranged to limit the travel of the link through the eccentric shafts 24 and 26. Except for the positions of the key stems 12, this linkage is identical for all printing keys.

Figure 4 shows diagrammatically that when the downstop shaft 24 is adjusted for a desired total key dip, the key dip and the angular displacement U of the powertrip bell crank 14 is the same for all the rows of key levers 13. The down-stop shaft 24 is in a universal adjustment of the total key dip which universally adjusts the angular motion U of the power-trip bell crank 14. In this figure, the power mechanism is of the type illustrated in Patent No. 2,737,279 granted March 6, 1956 to F. W. Schremp, while the power mechanism shown in connection with Figure 1 is shown in a copending application of common assignee, Serial No. 813,159 filed May 14, 1959. The effective key dip is the amount of total dip that is required to trip the power mechanism. This effective dip is adjustable by the eccentric up-stop shaft 26. which rotates the power-trip bell crank 14 about its fulcrum 27 to alter the gap 31} between the upper shouldered end 34 of the trip trigger 36 and the nose end 37 of a. trigger link 38, which latter is identified by the numeral 31 in the patent above referred to and controls the operation. of the mechanism power arm 35 through an eccentric cam roller 49 operated by the power roll 45. To increase the effective dip, the eccentric up-stop shaft 26 is adjusted to increase the extent of the gap 311 to allow additional lost motion of the trip trigger 36 before actuation of the power mechanism occurs.

Each unit of the key lever or parallel linkage 16 is held in normal position, as shown in Figure 1, by a spring 39, attached at one end to an anchor bail 41, suitably pivoted at its opposite endsfor swinging adjustment, and fastened at its opposite end to the trip trigger 36 which is pivoted as at 42 to the free end of the arms 43 of the power-trip bell crank 14. The latter carries a limit pin 44. for engagement with a ledge on the trigger 36 so. that the pull of the spring 39 tends to rotate the bell crank 14 in clockwise direction about pivot 27 and through arm 19 move the stop link 17 leftward to cause the stop edge 23 thereof to abut the rip-stop shaft 26. The depression of a key causes a counterclockwise rotation of the powertrip bell crank 14' against the yieldable resistance of spring 39. When the linkage'has caused link 17 to move toward the right, to contact the down-stop shaft 24, the force on. the key lever is released and the spring 39 returns. the linkage to its normal position. The springs 39 are varied in tension by adjustment of the anchor bail 41' to achieve the desired operating tension: on the keys, as shown. in Figure; 3, by operation of a disk 46 pivoted below the front edge of: the. keyboard frame. In like manner the adjustment of the. eccentric. down-stop shaft 24 isaccomplished; as shown in Figure 2, by an adjusting disk 47 pivoted below' the front edge of the keyboard frame. When the disk 46 is rotated it revolves a cam 48 to swing a lever 49 which in turn pulls on a tie rod 51 to rock the anchor bail 41 so that the tension of the springs 39 may be varied to give the desired touch control to the keys. In Figure 2 a different form of a stop link 52 is shown which has a tab 53 whose opposite edges provide abutments 54 and 56 with the abutment 54 of which the up-stop 57 coacts. The latter is an eccentrically mounted shaft which is preset to define the extent of the gap 30, as previously explained, while a down-stop 58 in the form of a bail 59, common to all of the stop links 52, is pivoted at its ends as at 61 and through a link 62 is operated by an eccentric cam 63 on the shank of the disk 47.

Each of the disks 46 and 47 is provided with a groove 64 for limiting the adjusting movement of said disks with respect to limit stops 66 extending downwardly from the front edge of the frame. A suitable dial can be used at the end of shaft 24 to adjust the same.

While I have shown and described what I consider to be' a highly desirable embodiment of my invention, it is obvious that changes in form could be made without departing from the spirit of my invention, and I therefore do not limit myself to the exact form herein shown and described nor to anything less than the whole of my invention as hereinbefore set forth and as hereinafter claimed.

What I claim as new and desire to secure by Letters Patent is:

1. In a typewriter, the combination with a power mechanism for operating a printing type bar including 'a trigger link and a trip trigger for engaging said link to'control the operation of the power mechanism; of downwardly movable key lever means, bell crank means for supporting the trigger and to which bell crank means an end of said lever means is pivoted, stop link-means pivoted to said bell crank means and movable horizontally on a downward movement of said lever means, said stop link means presenting a plurality of abutments, stop means coacting with said abutments for limiting horizontal movement of said stop link means in opposite directions to adjust the time of engagement of said trip trigger with said trigger link, and means for adjusting the position of said stop means.

2. A parallel key lever action for a typewriter or the like comprising a plurality of linkages of substantially like shape for each key including downwardly movable key lever means, recessed stop link means, bell crank means presenting arms of like length to which the opposite ends of the key lever means and the opposite ends of the stop link means are pivoted whereby downward dip of the key lever means will produce horizontal movement of the stop link means, trigger means on one of said bell crank means for tripping operation of a power mechanism, and stop means for adjusting the longitudinal movement of the stop link means to regulate the dip of the key lever means and the relative operation of said trigger means.

3. In a typewriter including power means for operating typing means, a parallel key action comprising a plurality of linkages of substantially like shape for each key including downwardly movable key lever means, recessed stop 'link means, bell crank means presenting arms of like length to which the opposite ends of the key lever means and the opposite ends of the stop link means are pivoted whereby downward dip of the key lever means will produce horizontal movement of the stop link means, one of said bell crank means controlling the operation of said power means, means engaging the recess of said stop link means for limiting the operation of said one bell crank means, a key tension means associated with one of said bell crank means, and means for varying the stress of said key tension means.

4. In ;a typewriter, the combination with a power mechanism for operating a printing type bar including a trigger link and a trip trigger for engaging said link to control the operation of the power mechanism; of downwardly movable key lever means, bell crank means for supporting the trip trigger and to which bell crank means for supporting the trip trigger and to which bell crank means an end of said lever means is pivoted, stop link means pivoted to said bell crank means and movable horizontally on a downward movement of said lever means, stop means coacting with said stop link means for limiting horizontal movement of the latter in opposite directions to adjust the time of engagement of said trip trigger with said trigger link, and means for adjusting the position of said stop means with respect to said stop link means. 7

5. In a typewriter or the like, a parallel key lever action comprising a plurality of linkages of substantially like shape for each key including downwardly moving key lever means, stop link means, key lever and powertrip bell crank means presenting arms of like length to which the opposite ends of the key lever means and the opposite ends of the stop link means are pivoted respectively, whereby typing operation of the key lever means will produce reciprocal movement of the stop link means, trigger means on said power-trip bell crank means for tripping operation of a power mechanism and means common to all of said stop link means for adjusting the amount of downward movement of said key lever means and the free movement of the trigger means to vary the time of operation of said power mechanism.

6. In a typewriter or the like, a parallel key lever action comprising a plurality of linkages of substantially like shape for each key including downwardly moving key lever means, stop link means, key lever and powertrip bell crank means presenting arms of like length to which the opposite ends of the key lever means and the opposite ends of the stop link means are pivoted respectively, whereby typing operation of the key lever means will produce reciprocal movement of the stop link means, trigger means on said power-trip bell crank means for tripping operation of a power mechanism and means common to all of said stop link means for adjusting the amount of upward movement of said key lever means and the downward spacing movement of said trigger means with respect to said power mechanism.

7. In a typewriter or the like, obliquely disposed key levers of like shape, key stems on said key levers arranged in banked rows, a stop link for each key lever, a key lever bell crank for connecting the forward end of each stop link with an associated key lever, a powertrip bell crank for connecting the rearward end of each stop link with an associated key lever, the arms of each of said bell cranks being of a length to provide horizontal linear movement of the stop links when the key levers are moved down, and means common to all of said stop links for adjusting the linear movement thereof in opposite directions.

8. In a typewriter of the character set forth in claim 7 including a power mechanism for each key lever for operating type bars in printing action, said power mechanism having operation controlling trigger means, a trip means carried by each power-trip bell crank for operating the trigger means, and the trigger and trip means being spaced to provide a gap tberebetween adjustable by the linear movement of said stop link to time the operation of said power mechanism.

9. In a typewriter of the character set forth in claim 8 wherein said trip means is pivoted to said trip bell crank, spring means for applying yieldable resistance to the trip bell crank through said trip means, and means for adjusting said spring means to vary the resistance of the key levers to typing action.

10. A typewriter as set forth in claim 5 including bail means common to all of said power-trip bell crank means, springs connecting the bail means and the bell crank means, and means for adjusting the bail means and ten- 5 6 sioning said springs for varying the operating resistance References Cited in the file of this patent of said key lever means in typing action.

11. A typewriter as set forth in claim 1 in which said UNITED STATES PATENTS stop means comprises a pivotally mounted down-stop 1,666,267 Shiek Apr. 17, 1928 and an eccentrically mounted up-stop, both said stops 5 1,741,690 Ely Dec. 31, 1929 being common to and arranged for coactive engagement 2,567,943 Kloski Sept. 18, 1951 with said abutments. 

